2lib: Add support for 64-byte nvstorage record

The calling firmware can set ctx->flags VB2_CONTEXT_NVDATA_V2 to tell
vboot that nvdata is a 64-byte record instead of a 16-byte record, or
equivalently, set the VBSD_NVDATA_V2 flag if calling the old vboot1
API.

If calling firmware does not (which is the current coreboot and
depthcharge default), then the 16-byte record is used, and V2 fields
return explicit default values.

Added the fw_max_rollforward V2 field, which defaults to 0xfffffffe on
V1.  This will be used by a subsequent CL.

Added unit tests to verify all that.

Added crossystem support, though it will only work with the current
16-byte records until firmware sets the VBSD flag and mosys supports
larger records.

(Note that because coreboot/depthcharge do not yet set the new context
flag, this CL should not change ToT firmware behavior.)

See go/vboot-nvstorage for design doc.

BUG=chromium:789276
BRANCH=none
TEST=make runtests

Change-Id: I43072ef153dfa016c051f560892af1fbb3508e3a
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/942031

3 files changed, 35 insertions, 10 deletions

diff --git a/host/arch/arm/lib/crossystem_arch.c b/host/arch/arm/lib/crossystem_arch.c
index 0a308416..d56f4e2e 100644
--- a/host/arch/arm/lib/crossystem_arch.c
+++ b/host/arch/arm/lib/crossystem_arch.c
@@ -260,7 +260,7 @@ static int vb2_read_nv_storage_disk(struct vb2_context *ctx)
 		return E_FAIL;
 	snprintf(nvctx_path, sizeof(nvctx_path), NVCTX_PATH, emmc_dev);
 
-	if (size != sizeof(ctx->nvdata) || (size + offset > SECTOR_SIZE))
+	if (size != vb2_nv_get_size(ctx) || (size + offset > SECTOR_SIZE))
 		return E_FAIL;
 
 	nvctx_fd = open(nvctx_path, O_RDONLY);
@@ -303,7 +303,7 @@ static int vb2_write_nv_storage_disk(struct vb2_context *ctx)
 		return E_FAIL;
 	snprintf(nvctx_path, sizeof(nvctx_path), NVCTX_PATH, emmc_dev);
 
-	if (size != sizeof(ctx->nvdata) || (size + offset > SECTOR_SIZE))
+	if (size != vb2_nv_get_size(ctx) || (size + offset > SECTOR_SIZE))
 		return E_FAIL;
 
 	do {
diff --git a/host/arch/x86/lib/crossystem_arch.c b/host/arch/x86/lib/crossystem_arch.c
index f026a14f..4921119e 100644
--- a/host/arch/x86/lib/crossystem_arch.c
+++ b/host/arch/x86/lib/crossystem_arch.c
@@ -158,16 +158,17 @@ static int VbCmosWrite(unsigned offs, size_t size, const void *ptr)
 int vb2_read_nv_storage(struct vb2_context *ctx)
 {
 	unsigned offs, blksz;
+	unsigned expectsz = vb2_nv_get_size(ctx);
 
 	/* Get the byte offset from VBNV */
 	if (ReadFileInt(ACPI_VBNV_PATH ".0", &offs) < 0)
 		return -1;
 	if (ReadFileInt(ACPI_VBNV_PATH ".1", &blksz) < 0)
 		return -1;
-	if (VBNV_BLOCK_SIZE > blksz)
+	if (expectsz > blksz)
 		return -1;  /* NV storage block is too small */
 
-	if (0 != VbCmosRead(offs, sizeof(ctx->nvdata), ctx->nvdata))
+	if (0 != VbCmosRead(offs, expectsz, ctx->nvdata))
 		return -1;
 
 	return 0;
@@ -177,6 +178,7 @@ int vb2_read_nv_storage(struct vb2_context *ctx)
 int vb2_write_nv_storage(struct vb2_context *ctx)
 {
 	unsigned offs, blksz;
+	unsigned expectsz = vb2_nv_get_size(ctx);
 
 	if (!(ctx->flags & VB2_CONTEXT_NVDATA_CHANGED))
 		return 0;  /* Nothing changed, so no need to write */
@@ -186,10 +188,10 @@ int vb2_write_nv_storage(struct vb2_context *ctx)
 		return -1;
 	if (ReadFileInt(ACPI_VBNV_PATH ".1", &blksz) < 0)
 		return -1;
-	if (VBNV_BLOCK_SIZE > blksz)
+	if (expectsz > blksz)
 		return -1;  /* NV storage block is too small */
 
-	if (0 != VbCmosWrite(offs, sizeof(ctx->nvdata), ctx->nvdata))
+	if (0 != VbCmosWrite(offs, expectsz, ctx->nvdata))
 		return -1;
 
 	/* Also attempt to write using mosys if using vboot2 */
diff --git a/host/lib/crossystem.c b/host/lib/crossystem.c
index 5a758616..38c9ed6e 100644
--- a/host/lib/crossystem.c
+++ b/host/lib/crossystem.c
@@ -98,11 +98,14 @@ static int vnc_read;
 
 int vb2_get_nv_storage(enum vb2_nv_param param)
 {
+	VbSharedDataHeader* sh = VbSharedDataRead();
 	static struct vb2_context cached_ctx;
 
 	/* TODO: locking around NV access */
 	if (!vnc_read) {
 		memset(&cached_ctx, 0, sizeof(cached_ctx));
+		if (sh->flags & VBSD_NVDATA_V2)
+			cached_ctx.flags |= VB2_CONTEXT_NVDATA_V2;
 		if (0 != vb2_read_nv_storage(&cached_ctx))
 			return -1;
 		vb2_nv_init(&cached_ctx);
@@ -118,10 +121,13 @@ int vb2_get_nv_storage(enum vb2_nv_param param)
 
 int vb2_set_nv_storage(enum vb2_nv_param param, int value)
 {
+	VbSharedDataHeader* sh = VbSharedDataRead();
 	struct vb2_context ctx;
 
 	/* TODO: locking around NV access */
 	memset(&ctx, 0, sizeof(ctx));
+	if (sh->flags & VBSD_NVDATA_V2)
+		ctx.flags |= VB2_CONTEXT_NVDATA_V2;
 	if (0 != vb2_read_nv_storage(&ctx))
 		return -1;
 	vb2_nv_init(&ctx);
@@ -834,18 +840,34 @@ static int ExecuteMosys(char * const argv[], char *buf, size_t bufsize)
 
 int vb2_read_nv_storage_mosys(struct vb2_context *ctx)
 {
-	char hexstring[VBNV_BLOCK_SIZE * 2 + 32];  /* Reserve extra 32 bytes */
+	/* Reserve extra 32 bytes */
+	char hexstring[VB2_NVDATA_SIZE_V2 * 2 + 32];
+	/*
+	 * TODO(rspangler): mosys doesn't know how to read anything but 16-byte
+	 * records yet.  When it grows a command line option to do that, call
+	 * it here when needed.
+	 *
+	 * It's possible mosys won't need that.  For example, if if examines
+	 * the header byte to determine the records size, or if it calls back
+	 * to crossystem to read the VBSD flag.
+	 */
 	char * const argv[] = {
 		InAndroid() ? MOSYS_ANDROID_PATH : MOSYS_CROS_PATH,
 		"nvram", "vboot", "read", NULL
 	};
 	char hexdigit[3];
+	const int nvsize = vb2_nv_get_size(ctx);
 	int i;
 
 	if (ExecuteMosys(argv, hexstring, sizeof(hexstring)))
 		return -1;
+	if (strlen(hexstring) != 2 * nvsize) {
+		fprintf(stderr, "mosys returned hex nvdata size %d"
+			" (expected %d)\n", (int)strlen(hexstring), 2 * nvsize);
+		return -1;
+	}
 	hexdigit[2] = '\0';
-	for (i = 0; i < VBNV_BLOCK_SIZE; i++) {
+	for (i = 0; i < nvsize; i++) {
 		hexdigit[0] = hexstring[i * 2];
 		hexdigit[1] = hexstring[i * 2 + 1];
 		ctx->nvdata[i] = strtol(hexdigit, NULL, 16);
@@ -855,14 +877,15 @@ int vb2_read_nv_storage_mosys(struct vb2_context *ctx)
 
 int vb2_write_nv_storage_mosys(struct vb2_context *ctx)
 {
-	char hexstring[VBNV_BLOCK_SIZE * 2 + 1];
+	char hexstring[VB2_NVDATA_SIZE_V2 * 2 + 1];
 	char * const argv[] = {
 		InAndroid() ? MOSYS_ANDROID_PATH : MOSYS_CROS_PATH,
 		"nvram", "vboot", "write", hexstring, NULL
 	};
+	const int nvsize = vb2_nv_get_size(ctx);
 	int i;
 
-	for (i = 0; i < VBNV_BLOCK_SIZE; i++)
+	for (i = 0; i < nvsize; i++)
 		snprintf(hexstring + i * 2, 3, "%02x", ctx->nvdata[i]);
 	hexstring[sizeof(hexstring) - 1] = '\0';
 	if (ExecuteMosys(argv, NULL, 0))